Kinetic Theory

1
Kinetic Theory
All matter is in constant motion-atoms, ions,
molecules-s,l,g,p (States of Matter) Gases1)Gas
is made of particles -atoms/molecules -mostly
empty space -weak forces between particles2)Gas
particles in constant motion -random3)Collisions
are perfectly elastic -energy transfer
100 -?T, ?KE-all particles have same KE KE
1/2mv2
Gas Properties
http//phet.colorado.edu/en/simulations/category/c
hemistry
constant
? ?
2
Gas Diffusion
Top Start of expt
5.1 The Gaseous State
Ammonia (17.0g/mol)
Hydrogen chloride (36.5g/mol)
Bottom End of expt
Ammonia diffused farther in same time, lighter
moves faster
3

• 0K -273C absolute zero everything
  freezes no KE-Gas pressure-force created by
  collisions of particles on object-Atmospheric
  pressure-force created by collisions of particles
  on an object caused by gravity-Barometer-measure
  s pressure 1atm 760mmHg 101.3kPa sea
  level-STP 0C, 1atm

4
Phase Change
-physical state of substance changes-melting,
freezing, evaporating, condensing,
sublimating(All examples of Physical
Changes)
5
Gas Laws
4 scientistsDaltonRobert BoyleJacques
CharlesJoseph Gay-Lussac Real Gases-particles
volume random motion collisions
elastic weak attractive forces
under pressure, liquefied and solidified Ideal
Gases-particles no volume random
motion collisions elastic no
attractive forces under pressure, not
liquefied and solidified Since real gases are
mostly empty space and attractive forces are
extremely weak, real gases act like ideal gases
in most situations!!!
http//phet.colorado.edu/en/simulations/category/c
hemistry
6
Daltons Law of Partial Pressures-In a mixture
of gases, the total pressure is the sum of the
pressures for each gas in the mixture. PT P1
P2 P3 . Vconstant Tconstant ex/A
scuba tank is filled with He, O2, and N2. The He
is used since it cuts down on the risk of
the diver contracting the Bends. How
much He is in the tank if the tank is
filled with 20atm N2, 4atm O2, and the total
pressure is 24.6atm?
http//www.youtube.com/watch?vN5xft2fIqQU
7
Boyles Law-Volume of a gas varies inversely
with pressure. P1V1 P2V2 Tconstant
V?, P? ex/A balloon partially filled to
capacity with N2. The balloon has 400mL of
N2 at 1.6atm pressure. What will happen to
the pressure if the volume is decreased to 350mL
by someone squeezing on the balloon?
8
Charles Law-Volume of a gas varies directly
with temperature. V1 V2 T1 T2 ex/A
balloon partially filled to capacity with N2.
The balloon has 400mL of N2 at 25C. What
will happen to the volume if the
temperature is increased to 45C by someone
heating it?
PconstantV?, T?
55 Gallon Drum
9
Gay-Lussacs Law-Pressure of a gas varies
directly with temperature. P1 P2 T1
T2 ex/A spray can of paint contains a constant
volume of paint at 16atm, 25C. What will
happen if the can is heated to 120C? It
will explode at 30atm.
VconstantP?, T?T must be in K
10
Combined Gas Law-Ties Boyles, Charles,
Gay-Lussacs Laws into one. Memorize this
one!!! Others are derived from it! P1V1
P2V2 T1 T2 ex/You go to Party City to
buy your friend a mylar balloon since she
is graduating. The conditions inside the
store are 22C. The balloon is filled with
5.6L of He at a pressure of 2atm. You put
the balloon in your car and drive home.
The temp inside your car is 34C, a hot
Summer day. Since the balloon is mylar, it only
expands to 5.7L. What is the final
pressure of the balloon? What will
probably happen to the balloon?
Tconstant .Boyles Pconstant
.CharlesVconstant .Gay-Ls
11
Ideal Gas Law-Used to calculate number of moles
for a gas. PV nRT n moles R0.0821
Latm Kmol ex/A propane tank
contains 20,000L of C3H8 at 14.5atm. If
the temperature outside is 35C, how many grams
of propane are in the tank? ex/A tank
of r22 (CHClF2) refrigerant has a volume of 20L
at 12.8atm and contains 1200g of
refrigerant, what is the
temperature of the refrigerant in the tank?

12
Liquids-particles in motion, slide, less
random-particles held together by weak
attractive forces unlike gases-KE liquid lt
gas-Vaporization-liquid?gas, below boiling
pt -Evaporation-vaporization in open space -?T,
?KE all particles .Those closest to surface
have enough energy to escape liquid. This is
how energy is removed from the liquid and why
temperature of the liquid remains the same as
the liquid is heated further. -Dynamic
Equilibrium-rate evaporationrate condensation
.Process doesnt stop. All particles have an
equal chance to evaporate and condense.
Adding more heat increases the rate of
evaporation and decreases condensation!-Boiling
Point-Temp which vapor pressureatmospheric
pressure .vapor escapes from liquid -Normal
Boiling Point-boiling point at 1atm ex/bpt
water Dover100C Nittany Mountains94C
13
Solids-particles packed close together in
organized pattern-xtal structure-particles do
not move, only vibrate/rotate-KE solid lt
liquid -?T, ?KE, ?vibrations/rotations
.melting-Melting Point-temp solid?liquid
.particles slide-no temperature increase until
all solid?liquid .equilibrium between solid
and liquid ?T, ?rate melting, ?rate
solidification-Ionic Compounds-? melting points
since strong attraction between
particles-Covalent Compounds-? melting points
since weaker attraction between
particles-Amorphous-solid lacking xtal
structure .properties solidliquid ex/LCD,
rubber, polymers, glass
14
-Heat of fusion-energy, 1g, melting
pt solid?liquid-Heat of solidification-energy,
1g, melting pt liquid?solid-Heat of
vaporization-energy, 1g, boiling
pt liquid?gas-Heat of condensation-energy, 1g,
boiling pt gas?liquid